Reactivity of anhydrous keggin-type heteropolyacids with alkylsilanes: synthesis and characterization

Anhydrous tungstic heteropolyacids react with alkylsilanes in the absence of solvent, leading to the evolution of hydrogen and the formation of a new kind of species where silicon is only weakly interacting with the polyoxometalate. The resulting material was characterized by various physicochemical methods including NMR, IR, and Raman spectroscopy. The most interesting feature is the unusual chemical shift of the (29)Si nuclei (ca. +50 ppm), which confirms the formation of a quasi-ionic bond between the organic and inorganic moieties. The weakness of this bond was also evidenced by chemical reactivity with nBu(4)NCl (leading to the formation of R(3)SiCl species) and oxygen. This new kind of structure can be of great interest in the field of microelectronics. Indeed the reactivity described in this article can be used and transferred easily in heterogeneous conditions to introduce defects in semiconductors.